1. Technical Field
The present disclosure relates to computer systems, and more particularly to a computer system having an updated power supply sequence and a method for operating the computer system.
2. Description of Related Art
A power supply on (PS_ON) signal is a TTL-compatible (transistor-transistor logic compatible) signal that allows a motherboard of a computer system to remotely control a power supply in conjunction with features such as soft on/off. When the PS_ON signal is at a TTL low level, such as a logical 0, the power supply will turn on full power, such as a 5-volt system voltage (VCC5V), a 12-volt system voltage (VCC12V), a 3-volt system voltage (VCC3V), and a 5-volt standby voltage (5V_SB). When the PS_ON signal is at a TTL high level, such as a logical 1, the power supply turns off all of the voltages except the 5V_SB. Once the power supply voltages are stable, the power supply will signal that fact to the motherboard with a power good (PWR_GOOD) signal. When the PWR_GOOD signal is effective, a POWER_OK signal received by a south bridge chip of the computer system is effective to indicate that the powers supplied to the south bridge chip are stable, and the computer system should start an operating system.
According to new platform specifications from Intel, the POWER_OK signal of the south bridge chip should be delayed a predetermined time to be effective after the PWR_GOOD signal is effective. Ordinary computer timing can no longer meet this new requirement.